In this proposal we will investigate the ability of neurotrophic factors delivered via genetically modified stem cell transplants into the eye to reduce the progression of damage and visual loss in an inducible rodent model of glaucoma (chronic ocular hypertension). Our preliminary studies in rodents with induced glaucoma and retinal ischemia demonstrated a therapeutic effect of neurotrophic factor treatment. We found that exogenous application of brain derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) delivered from biodegradable microspheres was temporally correlated with recovering visual function (pupil light reflex and electroretinogram) in rats affected with experimental glaucoma or retinal ischemia. The central hypothesis of this proposal is that transplanted, genetically modified bone marrow-derived stem cells can be used as effective neuroprotective agents to mediate preservation and rescue of visual function in the rat model of experimental glaucoma. We will test this hypothesis by delivering neurotrophic factors [brain derived neurotrophic factor (BDNF) and glia cell line-derived neurotrophic factor (GDNF)] via intraocular transplantation of genetically modified mesenchymal stem cells (MSCs) to eyes damaged by laserinduced chronic ocular hypertension and RGC injury. The long-term objective of this study is to develop effective methods to restore visual function in animal models of glaucoma, and to minimize or halt the process of neuronal death due to ischemic or pressure related insult. In this proposal we will use multiple, innovative approaches to advance toward these goals. First, we will use lentiviral vectors to genetically modify MSCs for production of neurotrophic factors. Second, we will employ cell transplantation of the MSCs as a therapy for neuroprotection in glaucoma. Third, we will turn to functional assays using computerized pupillometry and electroretinography (ERG) to determine the ability of transplanted MSCs and locally released neurotrophic factors to restore visual function after retinal injury. These noninvasive assays of visual function can be repeated over time to provide objective information about the status of the retina and optic nerve. We propose two Specific Aims of study: Specific Aim I: We will determine if transplanted MSCs, engineered to release neurotrophic factors, can provide neuroprotection to glaucomatous eyes. Specific Aim II: We will investigate a combination therapy by co-transplanting BDNF-MSCs and GDNF-MSCs to determine if they have greater neuroprotective activity than either by themselves. Engineered MSCs are especially attractive as neurotrophic factor delivery vehicles for several reasons. First, MSCs can be easily isolated, cultured, and propagated as a source of adult stem cells for autologous transplantation, inciting minimal host immune response. In addition, they can be easily engineered for production of exogenous proteins. Furthermore, these cells can survive in the environment of the eye and have the ability to integrate within the inner retina to serve as delivery vehicles for therapeutic proteins.